The unprecedented growth of industry since World War II and the introduction of new products to meet consumer demand has led to the need and desire to ship and handle larger quantities of raw materials in bulk containers. The shipping and handling of particulate solids of hazardous or toxic materials or contaminants of the ecosphere in a safe and environmentally acceptable manner has become a requirement of Federal, State and Municipal laws and regulations. Although the laws and regulations have gone a long way in protecting the public and environment from the deleterious effects of many of the harmful and obnoxious materials, they have created problems, both technical and economic for industry in complying with them. Materials such as asbestos, powdered pesticides, ground-up or particulate polymers and resins, pulverized minerals and even bulk shipments and handling of food stuff such as flour and other grains all create problems of varying degree to personnel and the environment when being discharged from bulk shipping containers and when not contained from the environment.
Many methods and techniques have been proposed and used for shipping and handling such materials when in particulate or powdered form. In spite of all the effort and money being spent to ship and handle them in a safe and environmentally acceptable manner, there continues to be a need for improved methods and apparatus for discharging or emptying bulk-bag shipping containers into process equipment in a way that does not contaminate the environment or expose personnel to the dust and fines that are always present during emptying, and in a way that is essentially clinically clean. The bulk-bags employed as shipping containers are made of flexible fabric, such as woven poly-propylene, and are capable of holding several hundred pounds of particulate solids. A generally available size has a capacity of about a ton, however they come in larger and smaller capacities and can be manufactured to hold several tons of particulate dry solids.
It is common for industry to use bulk-bag containers as an efficient means to ship, receive, and handle raw materials. It is cost-effective for the shipper, transporter, and recipient. A problem with the use of bulk-bag containers is the difficulty in emptying the contents of many dry particulate solids. During transit, many products compress and compact to a point such that they will not gravity-flow out of the discharge spouts in the bulk-bags. Methods such as reverse soil mechanics must be employed to break up the mass and allow it to flow again. Each material has its own characteristics and usually requires individual effort to overcome its particular problems. In addition and perhaps most important, the attachment of bulk-bags to process equipment involves an operator connecting and disconnecting the spouts at which time exposure of the contents of the bulk-bag takes place. This operator and environmental exposure is a problem inherent in the current methods used to discharge bulk-bags.